Species of special interest

Status and Trends
overall showing signs of stress; some improving, some deteriorating, and others unchanged
Concern, some improvements, some worsening
good data for some species in some areas showing clear trends; poor data for others

Medium confidence in finding
decline in amphibians and common landbirds
Red flag

KEY FINDING 17. Many species of amphibians, fish, birds, and large mammals are of special economic, cultural, or ecological interest to Canadians. Some of these are declining in number and distribution, some are stable, and others are healthy or recovering.

This key finding is divided into five sections:

Species of special interest are those with particular relevance to Canadians because of their special economic, cultural, or ecological importance in addition to their biodiversity value. Some groups of species, for example fishes, are important because the economy of a region depends upon them. Others, like caribou, have widespread cultural significance. These species are important because population declines often mean a loss of traditional lifestyles or a decline in economic sustainability. Species of special ecological importance play criticalroles in shaping the ecosystems in which they live or provide early warnings of ecosystem stress.

This key finding provides a brief overview of wildlife status in Canada and then focuses on amphibians, fishes using freshwater, birds, and caribou. More information on status of wildlife in Canada can be found in a complementary Canadian Biodiversity report, Wild Species 2010: the General Status of Species in Canada.1 More information on species at risk in Canada is provided by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC),2 on the Species at Risk Public Registry,3 and through provincial and territorial status committees.

Status of wildlife in Canada

Percent of native species assessed, 2010
Data for fishes were not available for 2010
Graph: status of wildlife in Canada. Click for graphic description (new window).
* Insects have not been fully assessed. Assessed groups include butterflies, mosquitoes, horse flies, black flies, bumblebees, lady beetles, ground beetles, predaceous diving beetles, odonates, and selected macromoths.
Source: adapted from Canadian Endangered Species Conservation Council (CESCC), in press1

Photo: Canadian tiger swallowtail © iStock.com/SoopySue Photo: eastern massasauga rattle snake © iStock.com/RMBolton Photo: bunchberry © iStock.com/eppicphotography

Canada is home to over 70,000 wild species. The risk of endangerment has been determined for 10,332 of these species, 8,613 of which are native. Seventy-seven percent of assessed native species were considered secure in 2010 and 12% were classified as At Risk or May be at Risk. Reptiles, freshwater mussels, and amphibians have the greatest percent of species at risk at 43, 24, and 20% respectively. In addition to these 8,613 species, Canada has assessed 5 Extinct, 35 Extirpated, and 1,426 non-native species, and 253 species outside their usual ranges. The major threats to Canadian wildlife are habitat loss, fragmentation and degradation, pollution and contamination, overexploitation, invasive species, disease, by-catch, and climate change.1

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Amphibians

Amphibians are an integral part of aquatic food webs, feeding on algae and insects at different life stages and serving as food for a wide range of predators, including dragonflies, fish, snakes, and birds. They are particularly sensitive to pollutants absorbed through their skin, which makes them good indicators of wetland contamination and degradation.1

In the Great Lakes Basin, four amphibian species, American toad, western chorus frog, northern leopard frog, and green frog, may have declined since the mid-1990s. Spring peeper is the only species out of eight monitored that has been increasing. However, the timeline is too short to be certain that these are long-term trends and not part of natural variation.1 In the St. Lawrence River, 27% of amphibians and reptiles are at risk within the highly developed river corridor.2 The northern leopard frog is considered Threatened in Alberta, red-listed in B.C., and assessed as Endangered (Rocky Mountain population), Special Concern (Western Boreal/Prairie populations) or Not At Risk (Manitoba and eastern populations) by COSEWIC.3

Batrachochytrium dendrobatids (Bd), a chytrid fungus of the skin, has been implicated in worldwide amphibian declines4 (see Invasive Non-native Species). Ranaviruses have also been responsible for mass die-offs of amphibians worldwide.5 Canada’s Boreal Shield,6 Prairies,7 and Mixedwood Plains6, 8 ecozones+ have documented cases of ranaviruses.

Amphibians in the Great Lakes Basin
Annual occurrence index (percent of monitoring stations where the species was recorded), 1995 to 2007
Graphs: amphibians in the Great Lakes basin. Click for graphic description (new window). iStock.com photos: Western chorus frog © rmarnold; Northern leopard frog © maimai; Bullfrog © Valmol48; Gray treefrog © HKPNC. dreamstime.com photos: American toad © David Anderson Wetlands, Algonquin Provincial Park; Ontario © Elena Elisseeva; Spring peeper © Jason Ross; Wood frog © Mircea Costina; Green frog © Electrochris.
Source: Archer et al., 2009.1
Globe

Global Trends

As of 2004, 43% of amphibian populations were in decline and 33% of all amphibian species were globally threatened. The dominant causes of declines worldwide are habitat reduction (North America and Europe), over-exploitation (Asia), and unexplained causes, possibly linked to disease (South America, Australia, and New Zealand).9

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Fishes using freshwater habitat

Fishes occur in almost all aquatic habitats and represent the largest group of vertebrates in the world.1 Although freshwater is relatively scarce globally, covering only 1% of the Earth’s surface, about 43% of the 29,000 to 32,000 fish species live in freshwater for at least part of their lives.2, 3 With over 8,500 rivers and two million lakes, covering almost 9% of the total land area,4 Canada has a disproportionate amount of the global freshwater habitat, but only about 200 species of native freshwater and diadromous fish. (Diadromous fishes use both marine and freshwater.2)

Fishes are among the world’s most important natural resources, providing numerous goods and services, including an annual global harvest of 92 million tonnes; 10.1 million tonnes from inland waters, most of which is freshwater.5 The commercial freshwater harvest in Canada is over 32,000 tonnes and valued at almost $68 million.6

This section is further divided into the following four topics:

Globe

Global Trends

An estimated 37% of the world’s freshwater fishes are threatened with extinction.17

Native freshwater and diadromous fishes at risk

Number of Extirpated, Endangered, Threatened, or Special Concern species
Graph: freshwater and diadromous fishes at risk. Click for graphic description (new window).
Note: Diadromous fish use both marine and freshwater. Trends reflect a combination of changes in the condition of species as well as the addition of new information.
Source: data compiled by Hutchings, 20108 from Hutchings and Festa- Bianchet, 20097 and COSEWIC, 20109

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) has assessed 18% (35 species) of freshwater and diadromous fishes as Endangered or Threatened throughout all or parts of their ranges. Fifty-eight species (29%) have been assessed as at risk, which includes species assessed as Extirpated and of Special Concern, as well as those that are Endangered or Threatened.7-9 The number of fishes at risk has been growing since the 1980s. The leading causes of declines in Canadian freshwater fishes are habitat loss and habitat fragmentation – caused by dams, weirs, roads and degradation of the riparian zone – and non-native aquatic species.3, 10-12 Overfishing, pollution, climate change, and interactions between wild and farmed species are also linked to declining populations of freshwater fishes.2

Sturgeon, species at risk

Photo: juvenile sturgeon © Traci JensenAll 24 species of sturgeon in the world are at risk, although definitions of “at risk” vary. Two of the five species in Canada are classified as Endangered or Threatened.13 White sturgeon, the largest freshwater fish in Canada, is restricted to the west coast of North America.14 Its size (up to 6 metres), longevity (over 100 years), and late maturity (14 to 30 years), make it especially vulnerable to overexploitation and habitat degradation.15 Of the six B.C. white sturgeon populations, three are declining (Columbia, Kootenay, Nechako), one is now more stable, with some fluctuations (lower Fraser), and two are stable (mid and upper Fraser). Poor juvenile survival, linked to river diversions, changes in sediment quantity and quality, and water flow regulation, associated with dams, are the primary reasons for endangerment of the three declining populations.15, 16

White sturgeon, Nechako River populations
Juvenile production, 1945 to 1990
Graph: juvenile white sturgeon production, Nechako River populations. Click for graphic description (new window).
Source: McAdam et al., 200516

Lake sturgeon once sustained large commercial fisheries. Reductions of 50 to 98% have been observed in western Canadian rivers and lake sturgeon have disappeared from the Red-Assiniboine River and Lake Winnipeg. Great Lakes populations have been reduced to a fraction of their original size, and populations in the Ottawa and St. Lawrence rivers are showing recent declines. Before the turn of the century, overfishing was the main threat to lake sturgeon. In recent years, declines are attributed to habitat fragmentation and degradation in the Great Lakes, as well as overfishing, dams, contaminants, and invasive species elsewhere.13

American eel

American eel in Ontario
Average number (thousands) of eels per day at R.H. Saunders Hydroelectric Dam, 1974 to 2005
Graph: American eel in Ontario. Click for graphic description (new window).
Note: no data are available for 1996.
Source: Ontario Ministry of Natural Resources, 201034

The American eel is an example of a once abundant species that is now listed as Special Concern by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Since the 1970s, populations have declined by 99% in the upper St. Lawrence34 and less extreme declines have been observed in both the lower St. Lawrence and Gulf of St. Lawrence.35, 36 The long life span of American eels, combined with their vast migration distances of up to 4,500 km, make them vulnerable to a wide range of stressors, such as mortality in hydroelectric turbines, physical barriers such as dams, overharvesting, and habitat alteration. Climate change, resulting in changes to ocean currents that carry eel larvae from the spawning grounds, may also contribute to population declines. American eels once provided both subsistence and commercial fisheries in Canada.36

Prey fishes in the Great Lakes

Trends in prey fish biomass based on annual bottom trawl surveys
Map and graphs: population trends of prey fishes in the Great Lakes. Click for graphic description (new window).
Source: adapted from Environment Canada and U.S. Environmental Protection Agency, 200937

The term prey fish refers to fish species that are the main food items of popular commercial and sport fish. A fish is considered a prey fish if it remains small in size, usually feeds on zooplankton or bottom-dwelling species, and is abundant enough to feed a predator fish population.38 Prey fish make up the majority of fish biomass and are the foundation of the Great Lakes fishery (see commercial fishing), as they are eaten by predatory fish such as trout, walleye, and bass. Prey fish include native species such as slimy sculpin, trout-perch, cisco, and bloater, and also non-native species such as alewife, rainbow smelt, and round goby. Declines in prey fish populations have been occurring since the 1980s and 1990s. The most likely causes are: stocking of Pacific salmon, which was done to reduce non-native prey fish; reductions in nutrients; and non-native zebra and quagga mussels, which filter nutrients from the water column and reduce food for the invertebrates that prey fish eat.37

Sockeye salmon © iStock.com/RKoopmans
Sockeye salmon

Salmon

Canadian lakes and rivers provide spawning habitat for five species of wild salmon on the West Coast18 and one on the East Coast. Wild salmon are a staple and a cultural foundation species for Aboriginal Peoples.19, 20 They are the basis of commercial, recreational, and Aboriginal food, social, and ceremonial fisheries on both coasts.20, 21 Wild salmon are revered by Canadians, in part because of the mystique of their life cycle – after growing in the ocean they migrate long distances to spawn in freshwater.

Fraser River sockeye returns

Number of returning salmon (millions), 1952 to 2009
Four graphs: Fraser River sockeye returns for four cohorts. Click for graphic description (new window).
Note: it takes four years for most sockeye to return to spawn after hatching.
Source: adapted from Lapointe, 201022
Fraser River sockeye survival
Productivity index (returns/spawner)
4-year running average, 1952 to 2008
Graph: Fraser River sockeye survival. Click for graphic description (new window).
Source: Fisheries and Oceans Canada (DFO), 201023

 

The Fraser River is legendary for its sockeye salmon runs. Since the 1990s, the number of returning sockeye has fluctuated widely, depending on the cohort (see graphs for the four cohorts above), while the survival rate – the proportion of fish that grow to adults and return to spawn – has been declining. In 2009, only 1.5 million adult sockeye returned – the lowest number since 1947. A scientific panel investigating the evidence for declining adult returns concluded that the major cause has been unfavourable physical and biological conditions in the Strait of Georgia, combined with freshwater and marine pathogens.23, 24 In 2010, mid-summer estimates predicted the largest Fraser River sockeye run since 1913.25

In some years, warming water and reduced flows due to climate change have impacted salmon migration, spawning, and rearing success. Sockeye survival and spawning are impaired as river temperatures increase above stock-specific thresholds.26, 27 Since the 1950s, mean summer temperatures in the Fraser River have increased by approximately 1.5°C.26, 28 This trend is likely to continue, increasing the probability of sockeye being exposed to water temperatures that will impair their survival.29

Atlantic salmon population trends

Hundreds of fish, 1970 to 2005
Map and graphs: Atlantic salmon population trends. Click for graphic description (new window).
Source: adapted from Gibson et al., 200630

Returns of Atlantic salmon to many rivers in North America have declined since the 1980s or 1990s, with northern populations increasing and southern populations remaining at low levels.30 For example, in inner Bay of Fundy rivers, runs of 30 to 40 thousand fish in the mid-1980s have been reduced to a few hundred fish, and in southern Nova Scotia, most salmon exist only as remnant populations or have been extirpated.31, 32 Although the factors contributing to low marine survival are largely unknown, freshwater declines are a result of the effects of dams, loss of spawning habitat, invasive species, increases in stream temperatures, siltation, contaminants,33 poaching20 and, in southern Nova Scotia, acid deposition.20, 32

Photo: recreational fishers, interior British Columbia lake © iStock.com/MarvinBeatty
Interior British Columbia lake

Commercial freshwater fishing

Commercial fish production in Lake Winnipeg
Tonnes (thousands), 1883 to 2006
Graph: commercial fish production in Lake Winnipeg. Click for graphic description (new window).
Source: adapted from Manitoba Water Stewardship Fisheries Branch as cited in Shipley and Kling, 201039

Lakes and rivers in Canada support significant commercial fisheries. Lake Winnipeg supports the largest commercial fishery in Manitoba, valued at approximately $20 million per year. Commercial fish production has been highly variable in Lake Winnipeg over the past 125 years, both in the amount of fish and the species harvested. For example, a dramatic decline in fish production from 1940 to the1960s was followed by an increase since the 1970s. Walleye production is now at historical highs and is the most important fishery species. Sauger, on the other hand, have been declining since the 1970s. Walleye are benefitting from the invasion of rainbow smelt and nutrient enrichment. These same factors are believed to be driving the decline in sauger.39, 40

The Great Lakes commercial fishery has an annual dockside value, in Ontario, that fluctuated between $29 and $37.5 million between 2004 and 2008,41 contributing $850 million per year in direct and indirect benefits to the Ontario economy. The overall commercial harvest has been declining since the 1980s. The main species harvested today are walleye and yellow perch, both native species, and rainbow smelt, a non-native species.42 Overfishing and predation by the non-native sea lamprey led to the collapse of lake trout in the late 1950s. Restoration, including stocking, has maintained a fishery, and lake trout are now reproducing in Lake Superior and Lake Huron.37, 43

Recreational freshwater fishing

Number of fish (millions), 1995 to 2005
Graph: recreational freshwater fishing. Click for graphic description (new window). Photo: Recreational fisher © Rob Stenner.
Source: adapted from Orok and Johnson, 200544

Approximately 3.2 million people participated in freshwater recreational fishing, or angling, in 2005, down from 4.2 million in 1995. The reduction in number of anglers has resulted in a reduction in the number of fish caught and the number of fish retained. It has also had an economic impact. Direct expenditures on angling were about $2.5 billion in 1995, 2000, and 2005. Although the dollar value of expenditures has not changed, this represents a 19% decrease in expenditures over 10 years, when adjusted for inflation. Anglers concentrate on some of the same species as the commercial fishery, namely walleye and yellow perch, although other species, such as brook trout, rainbow trout, bass, and northern pike, are also important. In 2000, the Year of the Volunteer, Canadian anglers dedicated over a million days to habitat clean-up and other activities related to improving recreational fishing.44, 45

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Birds

Birds are widespread, readily observed, feed at many levels of the food web, and are responsive to environmental change, making them good indicators of ecosystem health. Birds play an important ecological role, providing food for other species, dispersing seeds, controlling insects, pollinating plants, and modifying habitat. Many also have economic and cultural significance – providing humans with food, recreation, enjoyment, and study and playing an important role in many cultures.

Over the past 20 years, the status of the world’s birds has deteriorated, with more species moving closer to extinction.1 Of particular concern are declines in formerly common species.1 In the last 40 years, 20 common North American bird species lost over 50% of their populations.1, 2 Birds are also shifting their ranges northward in response to climate change – nearly 60% of the 305 species found in North America in winter moved northward by an average of 1.4 km per year (56 km over the last 40 years)3 and breeding ranges of southern North American species have shifted north by an average of 2.4 km per year.4

Canada provides crucial breeding, migrating, and wintering habitat for a significant percentage of the world populations of many species. Nevertheless, the status and trends of birds in Canada are only partially understood. Good data exist for many species, particularly in southern Canada; however, only localized data exist for many others, particularly in the North.

This section is further divided into the following four topics:

Globe

Global Trends

Globally, over 150 species of birds have been lost since the 16th century and one in eight is currently threatened with extinction. The last 20 years have witnessed a steady decline of bird species in terrestrial, freshwater, and marine ecosystems. Between 1988 and 2008, the status of 225 bird species was elevated to a higher level of risk.1

Photo: western sandpipers © Jason Puddifoot
Western sandpipers

Shorebirds

Sixty percent of North American shorebirds breed in the Arctic, with the Canadian Arctic providing 75% of the breeding range for 15 of 49 common species.5 Canada has migration sites of great importance as well, including at least three of hemispheric significance – the Bay of Fundy, the Fraser River estuary, and Chaplin/Old Wives/Reed Lakes in Saskatchewan.6 Some southern breeding areas, for example the Prairies, are of global importance to some species.7

Data on shorebird populations are patchy in Canada, but most information indicates declining trends.7-9 Of the 35 species examined in 2000, 49% showed significant declines somewhere in their range.5 The most complete datasets in Canada include the Breeding Bird Survey and the Atlantic Canada Shorebird Survey. Results from these surveys indicate:

  • Between 1976 and 2007, 4 of 12 species (33%) of shorebirds breeding in southern Canada declined significantly. There were no significant increases.10
  • Between 1974 and 2006, 5 of 15 migrating shorebird species (33%) on the Atlantic coast showed significant declines.11, 12

Potential causes of declines of shorebirds include loss and degradation of habitat, climate change, changes in predator regimes (for example, increasing numbers of peregrine falcons may cause shorebirds to move through an area more quickly, leading to an apparent decline13), human disturbance, contaminants, and disease.5 Changes are expected to accelerate due to anticipated changes in Arctic breeding habitat,14 as well as flooding and droughts elsewhere in shorebird ranges7 as a result of climate change.

Photo: northern gannets © John Chardine
Populations of northern gannets like this one on Bonaventure Island, Quebec, have increased in North America since the 1950s

Trends in status of breeding seabird populations in Canada

Number of populations in each category, 1980s to 2000s
Graph: trends in status of breeding seabird populations. Click for graphic description (new window).
Note: only populations with significant breeding populations, long-term datasets, and those unaffected by terrestrial human activities are included.
Source: adapted from Gaston et al., 200915

 

 

 

Worldwide, the status of seabirds is deteriorating faster than any other bird group.1 In Canada, trends are regional in nature and result from a variety of factors, including climate change, fishing by-catch, resource extraction, transportation, and pollution.15-20 A trend to an earlier breeding date has been found in several populations,21-23 as have changes in diet and condition.24

  • Pacific – southern populations, influenced by the changes in sea surface temperature related to the upwellings of the California Current, have been declining since the 1970s.15 Declines may also be due in part to a mismatch in timing between breeding and peak of food availability.25 Populations north of the influence of the current, however, have generally increased since the 1980s.15
  • Atlantic – prior to 1990, populations generally showed positive trends. A major cold-water event in 1990, however, coinciding with overfishing, disrupted food webs,26-29 resulting in immediate change in diet, condition, and population, particularly for gulls.24 Populations of most diving seabirds increased over this period, in part due to closure of the gillnet fishery that had been drowning many birds.30
  • Arctic – with the exception of ivory gulls, which are declining rapidly, change in Arctic seabird populations is slow and possibly the result of events on wintering grounds in the Northwest Atlantic.31, 32 Changes in seabird diet and growth have been found to be related to reduction of Hudson Bay sea ice. This may have negative consequences for populations in the long term.32 Conversely, in the High Arctic, less sea ice may benefit the birds.33, 34

Photo: ivory gulls © Mark Mallory
Ivory gulls

Photo: ducks © iStock.com/4loops

Waterfowl

Waterfowl have been monitored cooperatively by Canada and the U.S. since 1948. Concern over declines in populations in the 1980s led to the development of a large international cooperative initiative, the North American Waterfowl Management Plan, to address the declines. Although many duck populations fluctuate widely among years and regions, overall trends for most inland breeding ducks show increases or no significant change between 1961 and 2009.43, 44 Nevertheless, the populations of some species remain low; for example, northern pintail, American wigeon, and greater and lesser scaup have declined significantly in the prairie and western boreal regions.43, 44

Population trends for ring-necked ducks and scaup, western boreal region

Millions, 1961 to 2009
Two graphs showing population trends of ring-necked duck and scaup in the western boreal region. Click for graphic description (new window).
Source: Canadian Wildlife Service Waterfowl Committee, 200943

 

 

 

Locator map of the western boreal region. Click for graphic description (new window).

 

 

 

 

 

Approximately 70% of scaup and ringnecked ducks breed in the western boreal forest and the two species share many life history traits.45 Nevertheless, scaup declined at an average of 1.7% per year between 1961 and 2009 while ring-necked ducks increased by 2.5% per year.43 Reasons for the decline in scaup remain unclear but hypotheses include: contamination or change in food resources; and reduced female survival or reproductive success due to changes in the boreal forest.46, 47 Another possible cause is a mismatch between timing of nesting and food availability due to temperature change for late- nesting species such as scaup.45 Population declines have also been found in other late-nesting species such as scoters.43, 45 Ring-necked ducks breed earlier.

American black duck

Over 90% of the world population of American black ducks breed in eastern Canada48 and the population declined by almost 50% between 1955 and 1985.49 One of the most abundant ducks in eastern Canada, the population has been stable at about 450,000 since 1990, although declines continue in the Mixedwood Plains.43, 44 Causes for the decline are not clear but likely include habitat loss due to development and agriculture49, 50 and displacement through competition with mallards,51 which have been expanding in abundance and range.49, 50, 52 Population increases in other areas could be due to changes in management practices, such as increased hunting restrictions.53

Sea ducks

Photo: king eider © iStock.com/eyebexData for sea ducks are limited because most breed in remote, inaccessible areas in the North.43 Existing data show a mix of trends. Reasons for declines are largely unknown,43 but declines in eiders may be related to harvest and avian cholera may be an issue.54

Upward green arrow mergansers in prairie, boreal, and Atlantic regions
Upward green arrow common goldeneye in prairie and Atlantic regions
Upward green arrow bufflehead in prairie and boreal regions
Downward red arrow scoters in prairie and boreal
Upward green arrow surf scoters in Atlantic43 regions
Downward red arrow long-tailed duck in boreal regions
Downward red arrow Arctic breeding populations of eiders54-58

 

Landbird populations in Canada

Percent change by habitat type, 1970s to 2000s
Graph: percent change in landbird populations by habitat type in Canada. Click for graphic description (new window).
Note: data for the 2000s decade includes only 2000 to 2006.
Source: Downes et al., 2010,35 adapted from Breeding Bird Survey data, 200736

 

 

 

Populations of landbirds in all habitat types except forest declined significantly from 1968 to 2006.35 No significant positive trends in any landbird groupings (by habitat, by foraging, or by migration strategy) were evident between 1968 and 2006, although significant positive trends were found for some individual species.35

  • Grassland birds, with more than 40% loss of total population since the 1970s, show significant steep declines in all regions of the country and for most species. This is consistent with declines throughout North America10, 37 and is thought to be due to a combination of habitat loss and the intensification of agriculture.35
  • Birds of other open habitats have been declining since the late 1980s. The assemblage contains several species of aerial-foraging insectivores, many of which are showing declines.35
  • The urban group is heavily influenced by two introduced species, European starling and house sparrow, which, although still abundant, are showing declines in Canada and Europe.35
  • The decline in shrub/early succession birds is strongly influenced by declines in relatively abundant sparrows.35 Significant declines were found in the Atlantic Maritime, Boreal Plains, and Boreal Shield ecozones+.
  • Similar to the U.S.,37 forest birds show little change overall, although data indicate a decline since the 1990s.35 Trends for individual species vary, with some showing declines while others are stable or increasing. There have been varying degrees of decline in the Pacific Maritime, Montane Cordillera, and Western Interior Basin ecozones+, and increases in the Prairie and Mixedwood Plains where birds have responded to increased forest cover. About 60% of Canada’s landbirds breed in the boreal forest.38
  • Aerial and ground-foraging birds show significant declines of 35 and 27% respectively since the 1970s.35 Aerial-foraging insectivores, such as swallows and flycatchers, stand out as a group showing large declines.39, 40 Causes remain unknown but likely include changes in food, climate, and habitat.
  • Long-distance and short-distance migrants showed significant declines of 21 and 24% respectively, while resident birds were unchanged.35 Short-distance migrants include many grassland species. Long-distance migrants include many aerial-foraging insectivores. Loss and fragmentation of habitat on the wintering grounds is one possible cause for decline.41, 42

 

Photo: eastern meadowlark © iStock.com/Canon_Bob Eastern meadowlark,
grassland bird, declined by 77%

Photo: American kestrel © iStock.com/pollyconn
American kestrel,
bird of other open habitat, declined by 45%

Photo: house finch © iStock.com/MichaelStubblefield House finch,
urban bird, increased by over 200%

Photo: mourning warbler © iStock.com/PaulTessier Mourning warbler,
shrub bird, declined by 48%

Photo: downy woodpecker © iStock.com/brm1949 Downy woodpecker,
forest bird, increased by 30%

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Photo: caribou © Anne Gunn

Caribou

Caribou are distributed across most of Canada and can play important ecological roles as herbivores influencing the structure of plant communities, as prey supporting populations of large and medium-sized predators and scavengers, and as a source of nutrients in otherwise nutrient-limited systems. Caribou are an integral part of many cultures, particularly Aboriginal cultures, which have developed with caribou over thousands of years.1

This section is further divided into the following two topics:

Globe

Global Trends

Caribou and reindeer have a circumpolar distribution in the world’s tundra and boreal zones. Wild populations have declined in Russia and are mostly extirpated from Europe, except for a small, stable reindeer population in Norway, and an increasing population in Finland.28 Loss of habitat and climate change are threats worldwide.29

Caribou of the Arctic and taiga

Caribou of the Arctic and taiga population trends
Based on information available in August 2010
Map: Caribou of the Arctic and Taiga population trends. Click for graphic description (new window).
Source: adapted from Gunn and Russell, 2010,2 CARMA, 2009,10 Magoun et al., 2005,15 Elliot, 199816

Abundance of northern caribou, like other northern herbivores, such as lemmings and hares, is cyclic. Caribou numbers generally increased from lows in the mid-1970s to peaks in the mid-1990s, returning to lows by 2009 that are, in some cases, similar to previous lows.2 Some herds, notably the Bathurst and Beverly, which calve in the central Arctic, have experienced severe drops in the past few years.3, 4 Current declining trends may be partly related to natural cycles in abundance.2

Abundance of Peary caribou, which live on the High Arctic islands and are listed as Endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC),5 is largely influenced by weather. Periodic severe winters trigger large-scale mortality and reduction in productivity.5 Populations have declined by as much as 98% on several islands.6, 7 During two winters in the 1990s, more than 95% of the Peary caribou population in the western half of its range was devastated by heavy snow and the formation of ice layers in the snow.6 Events like these are projected to become more frequent and more widely distributed with climate change.6, 8, 9

Significant changes on caribou ranges since the 1970s could prevent a recovery of some herds to previous peak numbers.10 These changes include the effects of climate change, including changes in wildfire,11 and an increasing presence of people and development, particularly mining and oil and gas activity.12-14 Caribou harvest by humans and predation are also known to affect abundance within some caribou herds.5

Forest-dwelling woodland caribou

Map and graphs: status and range of forest-dwelling woodland caribou populations. Click for graphic description (new window).
Source: range for boreal population and southern boundary of historical extent adapted from Environment Canada, 2008,17 range for southern and northern mountain populations adapted from Thomas and Gray, 200218

Forest-dwelling woodland caribou are relatively non-migratory and live in smaller groups than their northern counterparts. They divide their time between lichen-rich mature forest and open areas, including alpine tundra.18 Historically occurring over much of Canada, their distribution has retracted, with the southern boundary continuing to move northward.18, 20 Caribou had completely disappeared from Nova Scotia and New Brunswick by 1930.21

The status of many herds remains unknown; however, where data exist, declines are evident, particularly for the boreal17 and southern mountain populations.22 Woodland caribou are declining primarily because of loss and degradation of habitat and landscape fragmentation due to roads and other linear features. This is resulting in the isolation of populations and increasing vulnerability to predators.17, 23-25 Overharvest of the caribou, fire, and climate change are also considered factors in population decline.17, 18, 26 Generally, populations that are stable or increasing occur in remote areas with little or no industrial activity or where predator control has been used as a management tool.27

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